Hi, I'm brand spanking new to the forum, so I apologize if this is in the wrong space.

I own and work on a 1984 honda civ s1500. Best car I've ever owned, 140k miles on it. Ran like a charm until I drove her cross country.

She's been having idle issues. I don't have a tach, so I don't know how high the idle actually gets, but its easily above 1k. It only happens when the engine has warmed up. It occasionally fixes itself when coming to a full stop, but it seems random that it does. I've had this problem for a while, but only after replacing the alternator did the problem become worse. Originally I could put a little bit of gas on the engine in neutral and the idle speed would regulate. That is no longer the case.

I've tried adjusting the alternator belt, changing spark plugs and wires, adjusting the carburetor choke, I replaced the accelerator cable (it was damaged, I was hoping this would solve the issue) and tried cleaning the throttle body with break fluid cleaner (figured it wouldn't make it worse).

Also, since replacing the alternator, my alternator light has been on. I've been under the assumption that it is faulty/corroded wiring somewhere and is unrelated to the high rpms, which is my focus.

 

So, after working on balancing my fuel-air on my carb to try and help the problem, I've had an overnight issue. I've been having a loud squealing noise since putting in my new alternator. The squealing went away very quickly though, lasting only when I first started the car. After working on my carb, the squealing no longer goes away. Checked to make sure it wasn't the timing belt by spraying wd40 on it, but it changed nothing. Is this my water pump going bad? I'm going to try removing my alternator belt completely to see if the squealing goes away at all.

 

Fixed squealing by completely pulling off the alternator belt. Tried readjusting it, didn't change anything so I drove it around despite the incredible amount of squealing, progressively got worse until it just stopped squealing.

Magic. However, I do still have high idle speed issues. Anytime the vehicle gets above 1.5k rpms, the vehicle idles at or above the highest rpms it reached, but only after the vehicle has shifted into a new gear or is in motion (in neutral after start, the vehicles idle is fine). Anytime my vehicle comes to a stop after driving, the idle speed is excessively high. I often times have to break very hard just to get the vehicle to slow.

On my list of could be's:
Fuel Pressure Regulator
Leaky Vacuum Hose
Carburetor Rebuild
Dying Water Pump

 

Another update. I noticed while taking my car around the block today after working on the carburetor fuel air mixture that my high idling is related to how fast I'm going when I shift to neutral. If I'm in 5th and coming to a stop sign, I would normally throw it into neutral and coast to the sign, but this recently would cause my idle to stay really high. So I've been down shifting to help not ruin my brakes.

 

I made a huge mistake. Cooling fan switch died, and while I was replacing it, I broke the switch off inside the radiator. Radiator was original and I noticed a leak in it, so I just bought a new radiator. After installing it, I tried to adjust and fix my high idle issue again. Cleaned out the carb as best I could with carb cleaner. I found a broken vac hose in the back of the carb which I was able to fix. The carb started spitting gas out of the butterfly. I drove the car maybe 2 minutes to a nearby parking lot. The idle was high enough that I didn't need to touch the gas. As soon as I tried to touch the gas to clear the idle, I heard a "pop" from the engine and the idle dropped. It dropped super low. Low enough that the car stopped. I was able to get it into a park spot by applying a little bit of gas, but then giving the car gas did nothing, and the idle just got slower until the car died. Thought it was just flooded. When I tried to start the car again, it would start for a split second, run really rough, and shut off.

 

As you have found out.... high idle that cannot be controlled is usually a vacuum leak, and you probably have another big one as the engine cannot keep up with the amount of air being sucked by the engine.

Time to do a full review of all those vacuum hoses. You may have broken another piece, those carb are a real pita when something goes bad.

Do not try to adjust the float level, this will result in a major headache.

A pict will help a lot... pict of the initial loose vacuum hose, please!

Same issue, after I replaced the alternator with a rebuilt from Oreillys, the battery light started to come on... but does not stay on. I have installed a real voltmeter, and it has been fine for over 20 months.

The squealing is probably a loose belt, it is hard to tighten the belt and secure the alternator bolt.

And the tsm for your help, random page
http://www.redpepperracing.com/techn...a/aal.png.html

 

How do you not have a tach? All 1500S models had them factory sir.